7 Fascinating Facts About Narwhals

There are few creatures I find so fascinating as the narwhal. Like many tusked animals, this arctic whale has a majestic quality to it. In medieval times, its long, straight tusk was often given to royalty, passed off as a “unicorn horn.” In the 16th century, a narwhal tusk worth £10,000 was given to Queen Elizabeth. Today, the narwhal still holds our interest, and its tusk remains one of the most mysterious things about these creatures. Here’s what we know about them.

1. Its tusk is actually a tooth

While it might appear to be situated in the center of its head, the narwhal’s tusk is actually an exaggerated front left tooth that protrudes from the upper lip. The right front tooth is small, and usually remains in the mouth. Stranger still, while most teeth (including human teeth) have a hard exterior and a soft, sensitive interior, narwhal teeth are the opposite. “No big surprise. It's been opposite in every other way,” Martin Nweeia, a clinical instructor at the Harvard School of Dental Medicine, told NPR after making this discovery. “But to find a tooth that is soft on the outside and has its most dense part around the pulp was completely odd.”

2. The tusk can grow to be 10 feet long

Narwhal tusks grow throughout the animals’ entire lives and can reach incredible lengths. While the tusk as a whole is straight—the only straight tusk we know of, in fact—a closer look reveals that as it grows, it spirals to the left.

3. It can bend about a foot before breaking

Its tough core and soft outer layer result in a tusk that is both strong and flexible. It can bend significantly without cracking, which is important for a tusk as long as the narwhal’s.

4. We’re not entirely sure what it’s for

History has numerous explanations for the narwhal’s massive tusk. One theory is that it can be used as a weapon, though this claim lacks sufficient evidence. Another suggests it is an accessory for finding mates and asserting dominance, much like peacock feathers or deer antlers. But the most recent theory, produced by Nweeia and his team, suggests it acts as a sort of environmental sensor. According Nweeia’s research, the tusk is porous and full of nerves, taking in external stimuli like water pressure, temperature, and salinity, and sending information back to the brain. To test this theory, Nweeia fitted narwhals with a kind of “jacket” that insulated the tusk from environmental factors. Then, researchers pumped the jacket full of water samples of varying salinity levels to mimic different kinds of sea ice. They found that different levels of salinity caused the narwhals’ heart rates to fluctuate, indicating they could sense the change and had a physical reaction to it. “But regardless of the reason, the results suggest that narwhals can funnel water into their tusks to measure its salt concentration,” Nweeia said.

5. Not all narwhals have tusks

In most tusked animals, the tusks appear in both males and females. However, in narwhals, only the males and about 15 percent of females have tusks. This is confusing to researchers. If indeed the narwhal tusk is a mechanism for sensing the environment, as recent studies suggest, why wouldn’t such an evolutionary trait be inherited by females as well? This perhaps lends more evidence to the theory that the tusk is mainly an accessory for garnering attention and establishing dominance among males.

6. Their skin is rich in vitamin C

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In fact, there is roughly as much vitamin C in one ounce of narwhal skin as there is in one ounce of oranges. Narwhal skin is a primary source of vitamins for the Inuit people of the Arctic. According to the BBC, “without the narwhal it is doubtful whether the Inuit would have survived in some parts of the Arctic.”

7. There are none in captivity

Unlike their close relatives, beluga whales, narwhals do not thrive in captivity. In the '60s and '70s, several attempts at capturing and keeping narwhals resulted in all of the animals dying within several months. In fact, all narwhals kept in captivity have died. Some animals simply aren’t meant to be captured.

Gopher or groundhog? (If you chose gopher, you're correct.)

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Gophers and groundhogs. Groundhogs and gophers. They're both deceptively cuddly woodland rodents that scurry through underground tunnels and chow down on plants. But whether you're a nature nerd, a Golden Gophers football fan, or planning a pre-spring trip to Punxsutawney, Pennsylvania, you might want to know the difference between groundhogs and gophers.

Despite their similar appearances and burrowing habits, groundhogs and gophers don't have a whole lot in common—they don't even belong to the same family. For example, gophers belong to the family Geomyidae, a groupthat includes pocket gophers (sometimes referred to as "true" gophers), kangaroo rats, and pocket mice.

Groundhogs, meanwhile, are members of the Sciuridae (meaning shadow-tail) family and belong to the genus Marmota. Marmots are diurnal ground squirrels, Daniel Blumstein, a UCLA biologist and marmot expert, tells Mental Floss. "There are 15 species of marmot, and groundhogs are one of them," he explains.

Science aside, there are plenty of other visible differences between the two animals. Gophers, for example, have hairless tails, protruding yellow or brownish teeth, and fur-lined cheek pockets for storing food—all traits that make them different from groundhogs. The feet of gophers are often pink, while groundhogs have brown or black feet. And while the tiny gopher tends to weigh around two or so pounds, groundhogs can grow to around 13 pounds.

While both types of rodent eat mostly vegetation, gophers prefer roots and tubers (much to the dismay of gardeners trying to plant new specimens), while groundhogs like vegetation and fruits. This means that the former animals rarely emerge from their burrows, while the latter are more commonly seen out and about.

Groundhogs "have burrows underground they use for safety, and they hibernate in their burrows," Blumstein says. "They're active during the day above ground, eating a variety of plants and running back to their burrows to safety. If it's too hot, they'll go back into their burrow. If the weather gets crappy, they'll go back into their burrow during the day as well."

But that doesn't necessarily mean that gophers are the more reclusive of the two, as groundhogs famously hibernate during the winter. Gophers, on the other hand, remain active—and wreck lawns—year-round.

"What's really interesting is if you go to a place where there's gophers, in the spring, what you'll see are what is called eskers," or winding mounds of soil, Blumstein says [PDF]. "Basically, they dig all winter long through the earth, but then they tunnel through snow, and they leave dirt in these snow tunnels."

If all this rodent talk has you now thinking about woodchucks and other woodland creatures, know that groundhogs have plenty of nicknames, including "whistle-pig" and "woodchuck," while the only nicknames for gophers appear to be bitter monikers coined by Wisconsin Badgers fans.

Every year, the 45 million or so red crabs on the remote Australian territory of Christmas Island migrate en masse from their forest burrows down to the ocean to mate, and so the female crabs can release their eggs into the sea to hatch. The migration starts during the fall, and the number of crabs on the beach often peaks in December. This year, you don’t have to be on Christmas Island to witness the spectacular crustacean event, as New Atlas reports. You can see it on Google Street View.

Watching the sheer density of crabs scuttling across roads, boardwalks, and beaches is a rare visual treat. According to the Google blog, this year’s crabtacular finale is forecasted for December 16, and Parks Australia crab expert Alasdair Grigg will be there with the Street View Trekker to capture it. That is likely to be the day when crab populations on the beaches will be at their peak, giving you the best view of the action.

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Google Street View is already a repository for a number of armchair travel experiences. You can digitally explore remote locations in Antarctica, recreations of ancient cities, and even the International Space Station. You can essentially see the whole world without ever logging off your computer.

Sadly, because Street View isn’t live, you won’t be able to see the migration as it happens. The image collection won’t be available until sometime in early 2018. But it’ll be worth the wait, we promise. For a sneak preview, watch Parks Australia’s video of the 2012 event here.